• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.67-70
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• 1996

The values measured at different time and enumerated sequentially by homogenous interval is called time series. Its goal is to predict values in future by analysing the measured values in past. The stastical approach to time series prediction tend to be by a neural approach with difficulties in expressing the reationship among past data. In neural approach, the preblem is the acquisting of the enough training data in advance. The goal of this paper is that such problem is solved by generating another term as virtual term between terms in time series.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.846-850
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• 1996

Today's product development requires simultaneous satisfaction of low cost, high quality and fast time to market. It is, however, difficult for product designers and engineers to achieve this goal due to too many requirements. This study shows integrated Computer Aided Engineering (CAE) approach can help to achieve such goal. CAE can not only support designers when decision needs to be made during concept design period but also provide evaluation of the designed parts and guidance to the best design of products during detail design period. Furthermore, integration with virtual prototyping concept can reduce number of actual prototyping and consequently reduce product development cost and time considerably. In order to demonstrate its possibility, example of washing machine development using CAE and its results are presented in this study.

• Journal of Korea Game Society
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• v.8 no.1
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• pp.79-90
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• 2008

This paper describes a motivation-based hierarchical behavior planning framework to allow autonomous agents to select adaptive actions in simulation game environments. The combined behavior planning system is formed by four levels of specification, which are motivation extraction, goal list generation, action list determination and optimization. Our model increases the complexity of virtual human behavior planning by adding motivation with sudden and cumulative attributes. The motivation selection by probability distribution allows NPC to make multiple decisions in certain situations in order to embody realistic virtual humans. Hierarchical goal tree enhances the effective reactivity. Optimizing for potential actions provides NPC with safe and satisfying actions to adapt to the virtual environment. A restaurant simulation game was used to elucidate the mechanism of the framework.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2625-2627
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• 2002

A virtual laboratory for measurement and instrumentation must aim to realize an integrated environment. To achieve this goal, we designed and implemented a client/server distributed environment and developed a web-based virtual laboratory system for electronic circuits. The proposed virtual laboratory system is composed of four important components : Principle Classroom, Virtual Experiment Classroom, Evaluation Classroom and Overall Management System. Through our virtual laboratory, the learners will be capable of learning the concepts and theories related to electronic circuit experiments and how to operate the experimental equipments. Also, every activity occurred in our virtual laboratory is recorded on database and printed out on the preliminary report form. All of these can be achieved by the aid of the Management System. The database connectivity is made by PHP and the virtual laboratory environment is set up slightly differently for each learner. Finally, we have obtained several affirmative effects such as reducing the total experimental hours and the damage rate for experimental equipments and increasing learning efficiencies as well as faculty productivity.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.8-15
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• 2022

In this paper, we proposed the method of virtual reality-based surgical navigation to reproduce the pre-planned position and angle of the pedicle screw in spinal fusion surgery. The goal of the proposed method is to quantitatively save the surgical plan by applying a virtual guide coordinate system and reproduce it in the surgical process through virtual reality. In the surgical planning step, the insertion position and angle of the pedicle screw are planned and stored based on the virtual guide coordinate system. To implement the virtual reality-based surgical navigation, a vision tracking system is applied to set the patient coordinate system and paired point-based patient-to-image registration is performed. In the surgical navigation step, the surgical plan is reproduced by quantitatively visualizing the pre-planned insertion position and angle of the pedicle screw using a virtual guide coordinate system. We conducted phantom experiment to verify the error between the surgical plan and the surgical navigation, the experimental result showed that target registration error was average 1.47 ± 0.64 mm when using the proposed method. We believe that our method can be used to accurately reproduce a pre-established surgical plan in spinal fusion surgery.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.3
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• pp.157-162
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• 2007

The goal of researching a proper crowd animation is to design system that is satisfied with the reality of scenes, performance of system, and interaction with users to show the crowd vividly and effectively in virtual underwater world. In this paper, we smartly expressed the behavior patterns for flocks of fish in virtual underwater and we made up for the weak points in spending time and cost to produce crowd animation. We compared with the number of mesh, the number of fish, the number of frame, elapsed time, and resolution and analyzes them with the fish behavior simulating system. We developed a virtual underwater simulator using this system.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.369-378
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• 2001

Recently, according to the rapid development of Internet and IT, many applications and technologies related to Internet and IT have been studied and developed. The agent technology, which was an essential topic in early AI, is being researched with the combination of the recent network technologies. Mobile agent especially takes high interest of many researchers because of its mobility with which it can move around the internet and complete its goal. This paper presents a virtual market system using mobile agent, in which the transaction agents can do their transaction about some product with each other instead of real buyer and seller. The presented virtual market system consists of market agent, customer agent and database agent to provide the virtual market places for the effective completion of transactions.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1698-1701
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• 2006

In this research, fractal approach is applied to the realization of a virtual enterprise. Virtual enterprise is a temporarily built organization to cope with new business opportunity. It is composed of diverse business partners such as suppliers, manufacturers, customers, and service providers in value chains. Therefore, communication and interoperability problems between heterogeneous participants are one of the main concerns in developing collaboration models of a virtual enterprise. Fractal-based reference model can be a solution for this problem. The term 'fractal' is used to represent a participant of the value chains. There are many advantages when participants try to embody fractal-based collaboration model such as; (1) no restriction of inner configuration, (2) guarantee of autonomy, (3) easy implementation of interfaces, etc. Fractals are self-similar, however, this does not mean that they should have same configuration. In this paper, a fractal-based collaboration model for a virtual enterprise is proposed and described with (1) a formal formulation of fractal concept, (2) functional requirements and interfaces, and (3) a goal model as a driving force of the virtual enterprise.

• Journal of Korea Multimedia Society
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• v.12 no.12
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• pp.1819-1826
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• 2009

To enhance the automatic performance of existing predicting and planning algorithms that require a predefined probability of the states' transition, this paper proposes a multiple sequence generation system. When interacting with unknown environments, a virtual agent needs to decide which action or action order can result in a good state and determine the transition probability based on the current state and the action taken. We describe a sequential behavior generation method motivated from the change in the agent's state in order to help the virtual agent learn how to adapt to unknown environments. In a sequence learning process, the sensed states are grouped by a set of proposed motivation filters in order to reduce the learning computation of the large state space. In order to accomplish a goal with a high payoff, the learning agent makes a decision based on the observation of states' transitions. The proposed multiple sequence behaviors generation system increases the complexity and heightens the automatic planning of the virtual agent for interacting with the dynamic unknown environment. This model was tested in a virtual library to elucidate the process of the system.

• Journal of the Korea Computer Graphics Society
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• v.28 no.3
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• pp.13-21
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• 2022

In this paper, the goal is to investigate how manipulating the camera can minimize motion sickness and maximize immersion when a user moves in a virtual environment that requires vertical movement. In general, since a user uses virtual reality in a flat space, the actual movement of the user and the virtual movement are different, resulting in sensory conflict, which has the possibility of causing virtual reality motion sickness. Therefore, we propose three powerful camera manipulation techniques, implement them, and then propose which model is most appropriate through user experiments.